I've reluctantly come to the conclusion that the iOS app for RTM is given 2nd-class status in their product line. Two examples:

1. iOS 11 enabled lists and notes management apps to make direct use of Siri. These apps can use Siri just like the built-in iOS Reminders app. I assumed that RTM would roll this capability out with an update for iOS 11 (as their competitors have). Well, no. I was told that RTM already has Siri support (via CalDAV). While that was a nice hack it is no longer the best-of-breed solution.

Given the above I've been reviewing competitors and that led me to rediscover this:

2. The RTM iOS app STILL does not support location-based reminders. This has been in the RTM Android app for 5 years I believe, but not for iOS.

It seems to me that if you want a cross-platform solution and that full iOS support is important to you, there are better solutions out there than RTM.

I hope someone can convince me I'm wrong here. I've had a Pro account for 10 years and would rather not transition to another solution. However, quality iOS support is a must-have for me.